The traditional Japanese method for the preparation of a nutritional, non-alcoholic beverage from rice requires the blending of steamed or cooked rice with rice koji. The rice koji is prepared by inocculating steamed or cooked rice with the spores of the mold (Aspergillus oryzae) and cultivating the inocculated rice.
After cultivation or fermentation for periods between 4 and 48 hours, the saccharified mass is passed through a sieve or filter. Dependent upon the starting materials used, (polished or unpolished rice or combination thereof) the filtrate is a white to beige colored slurry having a distinctly sweet, rice-like taste. The texture and sweetness of the slurry is determined by the total solids and the degree of starch conversion and may be mildly sweet or thick and sweet (similar to a milk-shake). This nutritional beverage prepared from rice is commonly termed amazake.
Amazake may be made from brown rice or white rice. By definition, white rice is brown rice which has had the outer bran layer removed by polishing. The bran layer contains proteins, predominantly all the oil found in rice, fiber, vitamins and minerals. The bran layer is considered to have significant nutraceutical and nutritional value. Unfortunately the bitter taste and “pulpy” texture resulting from the bran layer and endosperm fiber, limits the usage of brown rice as compared to white rice. Current terminology as set forth by the USDA and the Whole Grains Council, establishes the term “whole grain” as referring to the whole grain including the endosperm and bran layer and any products containing whole grains as having “substantially all the nutrient value found in the whole grain inclusive of the bran and endosperm components”. In the patents of Mitchell et al., (U.S. Pat. Nos. 4,894,242 and 4,744,922 the term “whole grain” was used to distinguish head rice from rice having a reduced particle size such as brewers, brokens, or flour. However, these patents also specified the use of “brown or white” whole grain. Such use of the term, “whole grain white rice” is currently inconsistent with the current and common use of the term “whole grain” since white rice does not contain the bran layer and therefore is not a whole grain by the present definition. Definitions for brown rice, head rice, broken rice or brewers rice can be obtained from the USDA, and are herein incorporated by reference.
The amount of sweetness derived from the arnazake is dependent upon the total solids of the liquid and the amount of time the rice is allowed to culture with the koji under optimum conditions. Sweet amazake products resulting from long culturing times have an inherent problem of developing considerable sweetness as well as a “flat” or “sour” flavor. This flat souring presumably is the result of microbial action in the nutrient rich media as well as the oxidation of fats naturally occurring in the rice.
In some cases, culturing is terminated prior to the development of this flat souring. However, this reduces the sweetness by limiting the amount of conversion of rice starch to sugars such as glucose and maltose, and results in a slurry that is thick and more like a milk-shake in texture.
The use of enzymes as an alternative method for the liquefaction and saccharification of starch from grains and tubers other than rice is very well known for the production of 100% carbohydrate products including dextrins, fillers and sweeteners intended to be competitive with sucrose. In these products, usually made from corn, the starch-containing portion of the grain or tuber is first separated from the non-starch containing portions before enzymatic conversion. Thus, a relatively pure starch is obtained which can be enzymatically converted and processed to produce a pure carbohydrate product free of impurities.
Because of the preliminary separation of the starch fragment from the grain, not only is a pure carbohydrate product obtained but the enzymatic conversion process is uncomplicated and uninhibited by the fat, fiber and protein contaminants. Unfortunately, this enzymatic conversion process yields a relatively pure carbohydrate product and therefore does not have the nutritional advantages yielded by the traditional koji method involving whole or ground rice. The separation of the starch fraction of whole rice from the other nutritional components has been described in the literature.
One method for the separation of the protein and starch from rice grains was provided by Guraya (U.S. Pat. No. 6,737,099) who taught the use of high pressure homogenization to de-agglomerate protein and starch from amylaceous flours of cereals and beans in an aqueous slurry. The liquid products resulting from this methodology is a homogenous dispersion of individual protein and starch granules, which may readily be separated from each other by centrifugation. Additionally, these components of protein and starch may be spray dried together to achieve a protein coated starch. The technology by Guraya makes no mention of the formation of the fat-amylose complex or opaque suspension, and it can be assumed that the nature of the high pressure homogenizer not only de-aggregated the protein-starch aggregates but also the fat-amylose aggregates which are considerably weaker than the protein-starch aggregates.
Guraya does not teach any technology associated with the heating and enzymatic hydrolysis of the deaggregated protein and starch slurry resulting from high pressure homogenization of flours, but rather of the separation, isolation, and functionality of the uncooked starch and unheated protein component, and the possible recombination of these refined and deaggregated protein and starch components prior to spray drying.
Examples of beverage products developed for the Non-Dairy Milk market, include soy beverages which have been employed recently as a milk substitute in powdered, canned and aseptic packaged form. Disadvantages associated with these soy-based milk substitutes arise primarily because of the allergenic response that many people have toward soy products, the bean-like flavor of the products, and their common need for the addition of a sweetener. However, the high protein content of the soy beverage products has been a distinct advantage.
Other Non-Dairy Milk beverage products include composites and mixtures of flours, in particular rice flour in combination with maltodextrin, oils, and carbohydrates. The latter type product was disclosed by Servotte, Yves in U.S. Patent Application No. 2004021390. These blends as well as traditional Mexican beverages referred to as “Horchata”, are blends of the more refined ingredients including oil, glucose syrup, and maltodextrin that are added separately to the rice flour. These products are not whole grain nor do they contain substantially all of the nutrients found in whole grains. Additionally, the primary sweetness does not result from the enzymatic hydrolysis of the flour but rather from the sugar or glucose syrup that is added.
In U.S. Pat. Nos. 4,744,992 and 4,894,242, both issued to Mitchell et al., a nutritional rice milk is disclosed, which is produced using ground rice particles from white or brown rice. An aqueous slurry of the rice particles is heat treated with alpha-amylase enzyme (with and without the presence of protease) to achieve liquefaction and subsequently treated with glucosidase enzyme in a saccharification step. The aqueous heat treatment of the divided rice particles results in the irreversible binding of the fiber to the insoluble protein fraction that is subsequently and easily removed by sifting to result in the claimed product having less than “3.5% protein on a dry weight basis”. The latter product constitutes less than 50% of the protein available in the whole grain rice. These slurries resulting from the Mitchell process still retain an unwanted bitter taste as well as an undesirable “sweetness” that results from the required glucosidase during saccharification. Additionally, the Mitchell slurries, after removal of the protein and fiber pulpy aggregate to yield the claimed milk-like character and reduced protein content, have a significantly lower protein and fiber content than what is reported for whole grain brown rice. The products resulting from the Mitchell technology more closely resemble a translucent, non-fat, sweetened milk product even after homogenization with added oil.
Accordingly, there has been found to remain a need for improved rice liquids that can be employed either as a beverage or in the preparation of food products and that have a taste that is less sweet, less bitter, or less pulpy than what has been available from the rice milk beverages resulting from the Mitchell et al. patent (marketed as Rice Dream), or the more traditional form of the amazake or composite mixtures such as the Horchata. Because of the generally non-allergenic response to rice, it may be anticipated that such products may have a similar characteristic of being generally non-allergenic. Additionally, and more importantly, recent trends in the food industry (including the USDA food pyramid) have also emphasized the need for individuals to consume at least three servings of whole grains, or products containing whole grains, per day. The products of Mitchell et al., or the traditional Horchata, contain only a small fraction of the protein, fiber, vitamins and oil found in white or brown rice from which they are manufactured. Amazake products are too sweet or have a bitter aftertaste and are too pulpy resembling more a milkshake. Therefore, there still remains a need for a non-sweet, non-bitter, non-dairy, milk-like product made from hypoallergenic whole grains that retain substantially all of the nutritional components of whole grains such as brown rice or corn.